Roth Conversion Calculator
See how much tax a Roth IRA conversion costs now and how much fits in your current tax bracket.
About the Roth Conversion Calculator
Converting pre-tax IRA or 401(k) money to a Roth IRA adds the amount to this year's taxable income; future qualified withdrawals are tax-free. Conversions make most sense in low-income years, when you expect higher tax rates later, or to reduce future required minimum distributions. 'Filling up' a bracket means converting just enough to stay below the next rate. Higher income can also raise Medicare premiums (IRMAA, based on income two years earlier) and affect credits.
The formula
Conversion tax = tax(income + conversion) − tax(income)
Worked example
Example: Extra tax from converting = $6,280
- Inputs: Filing status: Married filing jointly; Other taxable income before deductions: $99,000; Amount to convert: $44,000; State income tax rate: 0%.
- Formula: Conversion tax = tax(income + conversion) − tax(income)
- Result: Extra tax from converting = $6,280
Things to keep in mind
- Uses 2026 federal brackets and the standard deduction; consider IRMAA, state rules and the 5-year rule.
Questions people ask
Can I undo a conversion?
No, recharacterisation of conversions was abolished from 2018.
Is there an income limit?
No, anyone can convert.
Sources
The rules and rates this calculator uses come from the official pages below. Its results are estimates, not an official determination, and rules change, so check the latest figures there before you act on them.